Wire looper



March 26, 1968 E. SCHROEDER WIRE LOOPER 3 Sheets-Sheet l Filed May 10,1965 s. V. RR n QD A l... mm f J ms v m 5 M N 3 E i W W muy @f, ON@ 3 2n..- .ia 1% /Q u 0 ID3 34 5 33 Cl March 26; 1968- Filed May lO, 1965 E.SCHROEDER WIRE LOOPER 3 Sheets-Sheet s.:

March 26 1968 E. scHRol-:DL-:R 3,374,808

WIRE LOOPER 5 Sheets-Sheet E filed may 1 0, 1965 Q Rwm ScHnasoER dl NUnited States Patent O 3,374,808 WIRE LOOPER Erwin Schroeder, Roselle,Ill., assignor, by mesne assignments, to Precision Scientific Company,Chicago, Ill., a corporation of Delaware Filed May 10, 1965, Ser. No.454,455 11 Claims. (Cl. 140-102) ABSTRACT F THE DISCLOSURE 'Ihe presentinvention relates to means for forming a loop at the end of a length ofwire for electrical or mechanical purposes.

It is an object of the present invention to provide a Wire looper whichis particularly suited for forming a loop on the stripped end of alength of wire to be used in wiring a control panel or the like wherethe wire is to be secured to a screw or stud either alone or with othersimilarly terminated wires.

It is a more specific object to provide a wire looper which forms aprecise, complete loop which is ironed at and which is thereforeparticularly suited to multiple stacking on a common treaded terminal.

It is another object to provide a looper which is extremely rapid andpositive and well suited to production line use and which operates, moreor less automatically, to produce a precise loop having a predeterminedstraight neck portion at right angles to the loop with little care orattention on the part of the operator and in which there is no risk ofdamaging the loop, for example, by forcible bottoming at the end of theoperating stroke.

It is still another object of the invention to provide a wire looperwhich may be easily adjusted for loop diameter, wire size and necklength thereby to accommodate all wires, both solid and stranded incommon electrical usage.

It is an object, notwithstanding the particular applicability of thedevice to electrical wires, to provide a looper which may be universallyused toprovide a flat loop termination on any wire regardless of theintended usage or material of which it is made, a device which issimple, requiring, in its simplest embodiment, only a single moving partand having a long inherent life.

Other objects and advantages of the invention will become apparent uponreading the attached detailed description and upon reference to thedrawings in which:

FIG. l is a perspective view of a wire looper constructed in accordancewith the present invention;

FIG. 2 is a fragmentary perspective showing the underside ofthe loopinghead used in FIG. 1;

FIG. 2a is a contour diagram defining the shape of the groove and camsurfaces on the looping head;

CCV

FIG. 3 is a fragmentary longitudinal section taken along line 3 3 inFIG. l;

FIG. 4 is a horizontal section taken along the line 4-4 in FIG. l,showing the means for providing lateral offset;

FIG. 5a is a fragmentary section taken along the line Sa--Sa in FIG. 3.

FIG. 5b is a view similar to FIG. 5a showing the automatic alignment andlateral crowding of the wire as the pilot is inserted;

FIG. 5c shows the final movement of the wire into the loop recess;

FIG. 6a is a fragmentary plan view corresponding to FIG. 5a;

FIG. 6b is a fragmentary plan view corresponding to FIG. 5b;

FIG. 6c is a section taken along the line 6c-6c in FIG. 5c;

FIG. 6d is similar to FIG. 6c, showing the completion of the loop;

FIG. 6e shows the loop prior to removal from the receptacle;

FIG. 7 is a plan view of a turret receptacle for forming loops ofvarious diameter and wire size;

FIG. 8 is an elevation corresponding to FIG. 7;

FIG. 9 shows a portable version of the present device;

FIG. l0 is an end view of the device shown in FIG. 9.

While the invention has been described in connection with certainpreferred embodiments, it will be understood that we do not intend to belimited to the embodiments shown but intend to cover the various*alternative and equivalent constructions included within the spirit andscope of the appended claims.

Turning now to FIGURE 1, there is disclosed a wire looper 16 including ahead 11 and arranged below it, a receptacle 12. The receptacle ismounted upon a base 13 which may, for example, be secured to the tableof a drill press. The head 11 is secured in the chuck of the drill presswhich has been indicated, in phantom, at 14. In operation the wireindicated at 15 is positioned in the receptacle and the rotating head 11is advanced downwardly, engaging the wire to form it into a loop. In thefollowing paragraphs the features of construction which account for theadvantages mentioned in the objects above will be spelled out in somedetail. During the discussion it will be convenient to consider threeportions of the stripped end of the wire, the tip portion 16 which isformed into the loop, the connecting neck portion 17 which is adjacentto it and the shoulder of the insulation 18.

Mounted axially within the head 11 is a pilot pin 20 preferably having apointed tapering end 21, and having its shank 22 received in an axialbore 23. The pilot pin is secured in place by means of a set screw 24 orthe like.

Prior to discussing the surface configuration of the forming head, moredetailed consideration may be given to the receptacle 12. The receptacleis preferably formed of a bushing 30 having a top or supporting surface31 and a central hole 32 which is just slightly larger than the pilot20. At its lower end the bushing is necked down as indicated at 33 forpress fitting in an opening 34 formed in a body 35 which may be ofmetal, plastic or other suitable material.

For the purpose of receiving and sizing the formed loop, the lip of thehole is surrounded by au annular recess 36, the cross sectionaldimensions of which correspond approximately to the diameter of thewire.

In order to position the wire while the loop is being formed, and forproducing well dened, straight neck portion 17 which is unaffected bythe action of the forming head, a radial notch 37 is formed in-theoutside facing wall of the bushing 30, in communication with the hole 32and recess 36. Such notch is preferably just slightly greater, in width,than the diameter of the wire. When the neck portion 17 of the wire isreceived in the notch the projecting tip 16 projects at a slight upwardangle overhanging the surface 31, thus insuring that the tip is in aposition to be engaged by the forming head. For the purpose ofpredetermining the length of the tip acted upon, a stop 40 is providedin the form of an upstanding slightly arcuate barrier. The stop is bentat right angles to form a sliding base portion 41, which is clamped inthe desired position by a set screw 42, a slot 43 providing thenecessary endwise clearance. By trial and adjustment technique the stop40 may be quickly set to provide a complete loop. As an alternative,land where the stripping of the wire has been accurately carried out, theshoulder of the insulation on the wire may be used for stop purposes,thereby making the stop 40 unnecessary. Thus, the

' wire 15 may be lowered into the notch 37 and pushed forwardly withlight pressure until the shoulder of the insulation 18 bottoms on theoutwardly facing surface 44 of the bushing. This establishes apredetermined tip length.

i, ',In' accordance with the present invention, the forming tool 11 isprovided with an end surface 50 having'a shoulder 51 which is spacedoutwardly from'the pilot pin and which engages the projecting tip of thewire as it is simultaneously rotated and brought down against thereceptacle. More'speciiically in accordance with the present invention,the endl surface on the forming head is formed with a groove whichextends in a generally chordwise direction and which has tapering sidesmerging with a land which is adjacent the pilot pin. Thus, as shown inFIGS. 2 and 2a, a groove 53 is formed in the end face having a smoothlytapered leading edge wall 54 for guiding the tip of the wire into thegroove, a trailing edge wall which is somewhat more abrupt and whichdefines the wire engaging shoulder 51, and a terminal portion S whichleads to a land 56 adjacent the pilot pin. The lgroove 53 is preferablymade smoothly tapering in depth from its mouth at`the periphery of theforming head to its terminus 55. Moreover, while the groove 53 may bemore or less straight, in the preferred construction the root of thegroove follows a path which is curved or hooked in the direction of thepilot pin.

For a more precise definition of the preferred groove contour, typicalcontour lines have been shown in FIG. 2a. By way of example, and in thecase of a forming head intended for use with wire within the rang'e ofl0 to 20 gage,the groove 53 may have a maximum depth at its outer end of1A; inch. It will be apparent to one skilled in the art, as thediscussion proceeds, that the groove dimensions may be scaled upwardlyor downwardly for larger and smaller sizes of wire.

In accordance with one of the aspects of the present inivention,rthe`1'ccept'acle is relatively movable and laterally biasedinto a position in which the hole 32 is slightly oiset with respect tothe axis of the pilot pin so that the Y point of the pilot prin alwaysengages the' same side of the wire, notwithstanding the fact that thetip of the wire is initially disposed in a diametrical postion wthrespect to the pilot hole 32. Thus, as shown in FIG. 5a, the recep tacle35 is offset to the left so that the tip of the pilot pin will engagethe side of the wire tip 16 which, fori clock- Wise rotation of theforming head, is destined to form the inside of the loop. In carryingout the invention, the b'ody 35 of the receptacle is preferably mountedfor limited lateral movement with respect Vto the base 13, for

4 I v example, by vpivoting the two members together, and a spring isinterposed between them so that-the receptacle is normally biased intoits offset position. In the present instance the body is pivoted to thebase by a pivot screw 60, with a clearance slot 61 being provided in theslide 41. A stop surface, for defining the degree of offset, ispreferably formed by a surface 62 in the base 13 arranged in the path ofmovement of a downward skirt'or extension 63 on the bushing 30. Bias isprovided b'y a small coil or hairpin spring 65 (FIG. 4) which encirclesthe pivot bolt 60 and which is anchored at its first end 66 to the base,the free end 67 pressing against the movable body 35. For the purpose ofaccommodating the spring and providing a shoulder for pressing by thefree end of the spring, a recess 68 is preferably milled out on theunderside of the member 35.

The operation of the device thus far described will be apparent uponconsidering the sequential views Sa-Sc and 6a-6e. It will be assumedthat the stripped end of the wire has been placed in the notch 37 andthat the stop 40 is adjusted to provide a tip length just sufficient fora complete wire loop. It will further be assumed that the formingV head11 is mounted in a rapidly rotating chuck 14 in a drill press or thelike, and that the chuck Y is lowered by either manual or automaticmeans. Because of the offset in the receptacle, the pointed end 21 ofthe pilot engages the right-hand edge of the wire tip'16.

Upon continued downward movement the pilot advances into the hole 32,camming or crowding the, receptacle into an aligned position as shown inFIGS. 5b, 6b, and simultaneously bending the wire at Aits point of entryinto .the recess 36. The point of the bend has been indicated at 70 inFIG. 6b. As the forming head continues to move downwardly the surface 50at the lower end of the head engages the portion of the wire tip 16which lies above the surface 31 on thereceiving-bushing. Momentaryslippage occurs until the groove 53 in the forming head rotates aroundinto register with thetip of the wire. YThe wire is thereuponguided'downwardly along the tapered sur-Y face 54toward the rootrof thegroove and Where it may be actedvupon by the shoulder 51. This is thecondition which is illustrated inYFIG. 6c. Because of the relativelysharp internal shoulder at the inner end of the notch 37V in thereceptacle -the wire is effectively locked in place and there is notendency for the wire tobe pulled-through the notch. l Continuedrotation of the head causes the shoulder 51 to Wrap the tip of the wireabout the pilot pin 20 with the trailing end being fed up the grooveuntil the loop, uponA completion of a single revolution, isi-closed(FIG. 6d).V

With downward pressure continuing to be applied, and with the headcontinuing to rotate rapidly, the land surface 56 on the forming headpresses against completed'loop,y pressing it into seated position in therecess 36. The lat-v ter isshown by the dot-dash lines in FIG. 5c.Pressing the loop into the recess performs two desired functions; in thefirst place the scuing by the'land surface 5 6 tends to iron the loopcompletely at and, secondly, byrea'son Yof the fact that the recess hasa precise diameter, the loop on the wire is accurately fsized resultingin a high degree of `consistency in lthe iinished'product. r

After the forming head is bottomed, indicatingcom-fY pletion of theforming operation, the head .is raised clear of the receptacle asindicated nYFIG. 6e, thus allowing the receptacle ,p`under the urging ofthe spring 65 to s napl back to its initial position. The looped wiremay be lifted out and a fresh piece of wire inserted followingwhich thecycle may be repeated on a production basis. Y

- In a normal production line setup relatively long runs will be madefor a given wire size and size of loop. Where it is desired to change toloop wiresY of different gauge, it is a simple matter to substitute abushing 30 in ,thereceptacle with one having a larger recess. Where theloop size other having an appropriate diameter. This may be accomplishedby loosening the set screw 24 or by substituting a slightly dierentlydimensioned head 11 in the chuck 14.

In accordance with one of the aspects of the present invention a widerange of wire size loop diameter may be accommodated by making thereceptacle in the form of a rotary turret having means for indexing to aselected position. Thus, as shown in FIGS. 7 and 8 a circular turret 80is provided, having a pivot screw 81, which is screwed into a base 82which may be clamped to the table of a drill press or the like. At eachsetting or station on the turret a hole, annular recess, and companionnotch are provided just as described in connection with the earlierembodiment. Thus, in one of the positions, which will be assumed to bethe active position, a hole 83 is provided surrounded by a recess 84,having a notch 85 leading to the outside edge. The outside edge may beflatted as indicated at 86 in order to determine the length of the notch85 and hence the length of the resulting neck portion 17 of the wire.For the purpose of establishing the indexed positions of the turret astop pin 90 projects upwardly from the base 82 into an elongated recess91 formed on the underside of the turret. To normally bottom one end ofthe recess 91 against the pin 90, thereby to determine an offsetposition, a biasing spring 92 is provided which is anchored to the baseat 93 and which carries at its opposite end a pin 94. A radial hole 95is provided at each of the working positions for selectively receivingthe pin.

Thus, when changing the setting it is suicient to pull the pin 94, liftand rotate the turret 80 until a selected recess 91 registers with thepin 90, following which the turret is dropped back into seated position.Insertion of the pin 94 into the corresponding hole 95 restores thetorsional bias and the subsequent operation is the same as previouslydescribed.

It is found that, once set up, the present device produces loops whichare completely consistent from oneto the next, loops which are flat,which form a complete circle, and which have a neck of predeterminedlength at right angles to the loop. Moreover, the device may be operatedon a high production basis as fast as an operator can insert and removethe wires, all without any particular care and attention. If desired,the forming head may be automatically reciprocated at a spacing speed.Where a change in loop size or wire gauge makes readjustment necessary,such readjustment may be brought about within a few seconds time by theoperator of the machine with little effect upon output. Moreover, wherecertain standard loop sizes and wire gauges are used, it will beapparent to one skilled in the art that selectable stops may be providedfor the slide 41 which predetermines the length of the wire tip.

One advantage of the wire looper just described is that the loops are soperfectly formed that the loop is uniform and washer like, therebypermitting many different wires to terminate on a common stud or bindingpost stacked one upon the other and charged with suicient force toinsure good electrical contact and with no risk that one loop may slideout from under vanother to destroy the integrity of the stack.

While the invention has been described in connection with termination ofelectrical Wires, it will be understood by one skilled in the art thatthe structure and techniques described are fully applicable wherever itis desired to form a loop on the end of a piece of wire and regardlessof the material from which the wire may be made.

`Both of the above described devices are intended'for bench usage, butit is one of the features of the present invention that the loopermechanism is well-suited for portable hand usage as, for example, in thewiring of switchboards and control devices of various kinds. Thusreferring to FIG. 9, there is shown a hand-operated tool in the form ofa pair of pliers having parallel jaws or anvils 101, 102 which, throughthe action of linkage, remain generally par-allel to one another as thehandles of the device are squeezed. The construction of the looperelements is similar to that employed in the earlier embodiments andcorresponding reference numerals, with addition of subscript a, havebeen used to designate corresponding parts.

For the purpose of rotating the head 11a, the shaft of the head isextended upwardly and carries a handle 105. In use, the stripped end ofa piece of wire is laid in the groove 31a and the handles are squeezedto secure a lateral crowding of the wire, followed by bottoming of thehead. vWhile squeezing pressure is continued, the handle 105 is manuallyturned to complete the loop, after which pressure is released permittingthe springs 106 to restore the jaws to open position.

For stripping the end of the wire, stripper blades 111, 112 are securedto the respective jaws. The degree of insertion of the wire with respectto the blades is determined by an adjustable stop 40a, which is clampedin adjusted position by clamping screw 42a.

I claim as my invention:

1. In a loop forming tool for forming a loop `on the end of a length ofwire having a tip portion and a neck portion, the combination comprisinga rotary forming head having an end surface and a central -pilot pinextending therefrom, a receptacle arranged opposite thereto having a topsurface with a hole for receiving the pilot pin, said receptacle havinga generally radial groove formed in the surface for receiving the neckportion of the wire recessed in the surface with the tip portion thereofextending across the hole occupying a position above the surface on theother side, a stop for defining a predetermined tip length, the endsurface on the head having formed therein a chordwise extending groove,and means for advancing and rotating the head for engagement of the tipby the groove for wrapping of the tip into a loop about the pilot pin.

2. In a loop forming tool for forming a loop on the end of a length ofwire having a tip portion and a neck portion, the combination comprisinga rotary forming head having an end surface and a central pilot pinextending therefrom, a receptacle arranged opposite thereto having a topsurface with a hole for receiving the pilot pin, said receptacle havinga generally radial groove vformed in the surface for receiving the neckportion of the wire recessed in the surface with the tip portion thereofextending across the hole occupying a position above the surface on theother side, a stop for defining a predetermined tip length, the endsurface of the head having a tip engaging shoulder radially spaced fromthe pilot pin, and means for advancing and rotating the head for.engagement of the tip by the shoulder for wrapping of the tip into aloop about the pilot pin.

3. In a loop forming tool for forming a loop on the end of a length ofwire having a tip portion and a neck portion, the combination comprisinga rotary forming head having an end surface and a central pilot pin eX-tending therefrom, a receptacle arranged opposite thereto having a topsurface with a hole for receiving the pilot pin, said receptacle havinga generally radial groove formed in the surface for receiving the neckportion of the wire recessed in the surface with the tip portion thereofextending across the hole occupying a position above the surface on theother side, a st-op for defining a predetermined tip length, the endsurface of the head having a tip engaging shoulder radially spaced fromthe pilot pin means for advancing and rotating the head for engagementof the tip by the shoulder for wrapping of the tip into a loop about thepilot pin, said receptacle having an annular recess about the lip of thehole and the end surface of said head having an associated land surfaceadjacent the pilot pin and opposite the recess for forcibly urging theloop' into the recess upon axial bottoming of the head for ironing ofthe loop by the land.

4. In a loop forming tool for forming a loop on the end of a length ofwire having a tip portion and a neck portion, the combination comprisinga rotary forming head having an end surface and a central pilot pinextending therefrom, a receptacle arranged opposite thereto having a topsurface with a hole for receiving the pilot pin, said receptacle havinga generally radial groove lformed in the surface for receiving the neckportion of the wire recessed in the surface with the tip portion thereofextending across the hole occupying a position above the surface on theother side, a stop for defining a predetermined tip length, the endsurface on the head having formed therein a groove for engaging the tipof the wire as the head is brought axially into engagement with thereceptacle for wrapping of the tip into a loop about the pilot pin, thereceptacle having an -annular recess about the lip of the hole with theend surface of the head hav- Ving an associated land surface adjacentthe pilot pin and opposite the recess for forceably urging the loop intothe recess upon axial bottoming of the head for ironing of the loop bythe land.

5. In a loop forming tool for forming a loop on the end of a length ofwire having a tip portion and a neck portion, the combination comprisinga rotary forming head having an end surface and a central pilot -pinextending therefrom, a receptacle arranged opposite thereto having a topsurface with a hole for receiving the pilot pin, said receptacle havinga generally radial groove formed in the surface for receiving the neckportion of the wire recessed in the surface while the tip portion of thewire` extends above the supporting surface on the lopposite sideof thehole, the pilot pin having a tapered end and the hole being slightlyoffset from the pilot pin so that the pilot pin engages the tip of thewire on a predetermined side thereof followed by lateral crowding of thewire as the pilot pin enters the hole, the end surface of the headhaving a tip engaging shoulder formed thereon for engaging the tip ofthe wire for wrapping of the tip into a loop about the pilot pin.

6. In a loop forming tool for forming a loop on the end of a length ofvwirehaving a tip portion and a neck portion, the combination comprisinga rotary forming head having an end surface and a central pilot pinextending therefrom, a receptacle arranged opposite thereto having a topsurface with a hole for receiving the pilot pin, said receptacle havinga generally radial groove formed in the surface for receiving the neckportion of the wire recessed in the surface with the tip portion thereofextending across the hole occupying a position above the surface on theother side, the end of the pilot pin being tapered and the hole beingslightly oset from the pilot pin so that the pilot pin engages the tipof the wire on a predetermined side thereof followed by lateral crowdingof the wire as the pilot pin enters the hole, the end surface on thehead having formed therein a groove for engaging the tip of the wire forwrapping it into a loop about the pilot pin.

7. In a loop forming tool for forming a loop on the end of a length ofwire, the combination comprising, a rotary forming head having an endsurface and a central pilot pin extending therefrom, a receptacle havinga top surface and a hole for receiving the pilot pin, Said receptaclehaving a radial groove formed in the surface for receiving the neckportion of the wire recessed in the surface while the tip portionthereof extends diametrically across the hole occupying a position abovethe surface on the other side, a stop on said receptacle for defining 'apredetermined tip length equal to the length'of the desired loop, meansfor biasing the receptacle into a normal position in which the hole.therein is slightly offset with respect to the axis of the pilot pin,said pilot pin having a pointed tapering end for entering between thetip of the wire and the side of the hole and so that as the pilot pin isfully inserted the receptacle is urged into a condition of alignmentaccompanied by lateral bending of the wire at the point where it entersthe hole, the end surface -on the head having a shoulder formed thereonspaced from the pilot pin for engaging the tip of the -Wire'and forwrapping the tip'into a loop about the pilot pin.

8. In a loop forming tool for forming a loop on the end of a length ofwire, the combinationcornprising, a rotary forming head having an endsurface and a central pilot pin extending axially thereform, areceptacle in the path of endwise movement of the head having a hole forreceiving the pilot pin, an annular recess in said receptaclesurrounding the hole, said receptacle having a radial` groovecommunicating with the recess for engaging the neck portion of the wirewhile the tip portion extends across the hole above the level of thereceptacle, a stop on said receptacle for defining a predetermined tiplength, the receptacle being laterally movable through a limited grangebetween a position in which the hole is slightly offset with respect tothe pilot pin and a position of alignment with the pilotvpin, means forbiasing the receptacle into the .offset position, the pilot pin having apointed tapering end for assuring engagement with a predetermined sideof the wire tip and so that as the head is axially advanced thereceptacle is crowded into an aligned position accompanied by bending ofthe wire at the point where the wire enters the receptacle, the endsurface of the head havinga generally chordwise groove formed thereinfor engaging the tip of the wire and for wrapping it into a loop aboutthe pilot pin, the end surface of the head further having a landadjacent the pilot pin for pressing the loop into the recess as the headmoves into a bottoming position.

9. In a loop forming tool for forming a loop on the end of a length ofwire, the combination comprising, a rotary forming head having an endsurface and a central pilot pin extending axially therefrom, a rotatableturret having a central pivot and having a plurality of holes spacedabout its periphery, each of said holes having an annular recess andhaving a radial groove communicating with the recess with the width ofthe recess and width of the groove varying incrementally from hole tohole, said turret having indexing means for positioning the selectedhole under the forming head, depending upon the gauge of wire to beaccommodated,it he end surface on the head having a shoulder spaced fromthe pilot for engaging the tip of the wire as the head is advanced andfor wrapping the same into a loop about the pilot, theV end surface onthe head further having a land adjacent the pilot for pressing thecompleted loop into the recess thus insuring that the loop is dat and ofpredetermined contour, said turret having means for applying rotationalbias and said indexing means including a plurality of stop surfaces fornormally positioning the holes in an offset position with respect to thepilot pin thereby to insure engagement of the pilot pin with apredetermined side of the wire as thepilot pin approaches the turret.

10. In a loop forming tool for forming a loop on the end of a length ofWire having a tip portion and a neck portion, the combination comprisinga rotary forming head having an end surface and a central pilot pinextending therefrom, -a receptacle arranged opposite there- Y to havinga top surface with a hole for receiving the pilot pin, means on thereceptacle for positioning the wire across the hole with the tip abovethe top surface, a stop for defining a predetermined tip'length, theendsurface of the head having a tip engaging shoulder radially spacedfrom the pilot pin, means for advancing and rotating the head forengagement of the tip by the shoulder for wrapping of the tip into aloop about the pilot pin, and means for establishing an initiallaterally oiset relation between the pilot pin and the wire so that thetip portion of the wire isl engaged by the shoulder.

11. In a loop forming tool for forming a loop on the endof a length ofwire having a tip portion and a neck portion, the combination comprisinga rotary forming head having an end surface and a central pilot pin eX-tending therefrom, a receptacle arranged opposite thereto having a topsurface with a hole for receiving the pilot pin, means on the receptaclefor positioning the Wire across the hole with the tip above the topsurface, la stop for defining a predetermined tip length, the endsurface of the head having a chordwise extending groove, means foradvancing and rotating the head for engagement of the tip by the groovefor wrapping of the tip into a loop about the pilot pin, `and means forestablishing an initial laterally oset relation between the pilot pinand the Wire so that the tip portion of the wire is engaged by thegroove.

References Cited UNITED STATES PATENTS 520,864 6/1894 Reynolds 140-1041,519,550 12/19'24 Pozgay 140-1025 1,526,716 2/ 1925 Neunherz 140-1042,593,083 4/1952 Adamo 140-104 FOREIGN PATENTS 892,885 10/ 1953 Germany.

CHARLES W. LANHAM, Primary Examiner.

E. M. COMBS, Assistant Examiner,

